Electric furnace.



No. 872,352. PATBNTED DEC. 3, .1907.

J. 0; KING. ELECTRIC FURNACE.

APPLICATION FILED JAN. 6, 1904.

3 SHEETS-SHEHT 1.

FIG. 2.

INVENTOR; WlT NESSES: J93. QM 0&M 51' ff/0171:3 16,

W m. GUQQQQAQCQL No. 872,352. PATENTED DEC. 3, 1907. J. C. KING.

ELECTRIC FURNACE.

APPLICATION FILED JAN. 5, 1904.

3 SHEETS-SHEET 2.

. TNVENTOR: WXTNXESS'ES: y filly/(2' :MW By Ai/mvzeys,

PATENTED DEC. 3, 1907.

J. C. KING. ELECTRIC FURNACE. APPLICATION FILED JAE. 5, 1904.

3 SEEETSBHEKT 3- F16. 6. k m

W I INVENTOR: WITNESSES: 2% QM I By A ftomeys,

' under similar conditions.

UNITED STATES PATENT OFFICE.

JESSE (JRITZ KING, 01" ST. UATIIARINES, ONTARIO, CANADA, ASSIGNOR TO THEWILLSON CARBIDE WORKS COMPANY OF ST. CATHARINES, LIMITED, 01 ST.(JAIHARIIIES,- CANADA,

A CORPORATION OF ONTARIO.

EIECTBIC FURNACE.

Specification of Letters Patent.

Patented Dec. 3, 1907.

Application filed January 6.1904. Seriel.Ro.1B7.B37.

To all whom it may concern:

Be it known that 1, Jesse Cnrrz KING, a citizen of the United States,residing at St. Catharines, in the Province of Ontario, Canada, haveinvented certain new and useful Improvements in Electric Furnaces, ofwhich the following is a specification.

Myinvention aims to provide certain improvemcnts in apparatus forelectric smeltmg or other electric furnace treatment, and especially forthe manufacture of calcium carbid or other substances which are formed 71n the manufacture of calcium carbid, for example, a mixture of lime orlimestone and carbon is fed into the furnace and the mixture is fusedand converted into calcium carbid, with the well known reactions. In theprocesses most commonly em loyed only the central portion of the materiais fused and reduced, so that the pig of carbid which is formed issurrounded by a crust of the unreduced or partially reduced mixture oflime and carbon. This crust is practically a waste product, andfurthermore the cost of separating it from the pure carbid is verygreat. This expense, and the public nuisance caused by the odor which adump pile of the crust makes, are very serious objections to the presentmethods of manufacture. Likewise according to the most common practice alarge part of the mixture outside of the crust in the furnace isunreduced, and has to be disposed of by being carried back and mixedwith fresh material, which is a matter of considerable ex ense andannoyance.

Iy present invention provides a furnace which can be operated to producea crustless carbid and to avoid the presence of any substantial quantityof unreduced material. All the material to be utilized in forming thecarbid is confined to the zone of fusion, so as to be completelyreduced. This is preferably done by passing the material through a diethe walls of which closely circumscribe the fused material and which dieseparates the unreduced material above from the reduced materialbeneath. The die preferably constitutes one of the electrodes, the otherelectrode being a pencil arranged with reference to the die so as toprovide a space between the two through which the material may bepassed. Preferably the die flares downwardly and the material is feddownwardly through the die. By reason of this construction thecongealing outer portion of the pig of carbid is easily separated fromthe wall 0 the die as it moves downward.

My invention contemplates the feeding of the material through the zoneof fusion by any suitable means, preferably by withdrawing the productas it is reduced so as to allow fresh material to enter the zone offusion, the rate of withdrawal being controlled either by hand or byautomatic regulating means.

Various other improvements are referred to in detail hereinafter.

The accompanying drawings illustrate embodiments of the invention.

Figure 1 is a longitudinal section, and Fig. 2 a horizontal section onthe line 22 of Fig. 1, illustrating one style of furnace; a completeelectric circuit being shown in connectlon with Fig. 1. Figs. 3', 4 and5 are respcctively a longitudinal and a transverse vertical section anda horizontal section on the line 55 of Fig. 3 illustrating another styleof furnace. Figs. 6 and 7 are vertical sections of other styles offurnaces, the former being a single-arc furnace and the latter adouble-arc furnace.

Referring to the embodiments shown in the drawings, and especially inFigs. 1 and 2, A is a carbon encil constituting one of the electrodes,and B are carbon blocks or sections connected with each other andconstituting all together the opposite electrode.

The inner ends of the carbons B are contiguous to each other, as shownin Fig. 2, so that they form substantially a die surrounding the pencilA. The pencil A is of such size as to leave an annular space C betweenthe opposite electrodes. This space may be rectangular as shown, orotherwise shaped. It is through this annular space, across which thecurrent continually passes, that the matcrial D is passed, and first liuefied into a pool, somewhat as shown at It, which subsequentlysolidifies into a pig F of carbid or other material, depending on theingredients used. With carbid, which solidifies at a very hightemperature, no cooling means is the chute.

ordinarily required, but for products which congeal at lowertemperatures the die may be cooled by a water jacket, as shown at e inFi 3, or otherwise.

lhe current is supplied from a generator G, preferably an alternatingcurrent generator. Preferably a transformer II of any suitable type isinterposed between the furnace and the dynamo, and reduces the highvoltage between; the primary leads J and K to a low voltage. between thesecondary terminals and leads J and K". Preferably the feed iscontrolled by lowerin the pig of reduced material at a rate not fasterthan that at which the furnace can work with the desired efficiency. Theseveral figures of the drawings show suitable arrangements for thispurpose. In Fig. 1 the pig is curved, and passes down through a fixedcurved chute L. Preferably this chute is larger than thejjpjgfrflas'fgsliown, andthe casting M which carries the carbons formin theelectrode B is so shaped as to permit t e passage of a portion of thematerial D outside of the die formed by the meetin ends of the carbon sothat the material is fe about the pig and preferably on all sides of itbetween the pig and the walls of the chute L. Any other suitablenonconducting material may be fed about the pig to prevent injury to thewalls of the chute by the high heat and to facilitate the passage of thecurved pig through In Fig. 2 the shape of the casting M is indicated,openings N permitting the passage of a portion of the material D asexplaine I A suitable mechanism for drawim out the pig F comprises aconveyer made of sections or flights 0 connected together to form acontinuous curved platform running on rollers P carried by the fixedstructure and moved downward by means of a line of teeth Q forming acontinuous rack which is in engagement with a (pinion R driven by a wormgear S controlle by a hand wheel T. The inner face of the sections 0 ofthe conveyer is substantial] in line with the inner face of the wall ofthe chute L. The guide rollers and operating parts of the conveyer arecarried by a second chute U in the upper open end of which successivesections of the conveyer are added from time to time as necessary.

The relative arrangement of the parts' of the complete furnace and themanner of supporting the several parts may be considerably varied. Asshown in Fig. 1 the furnace is supported upon standards V directlycarrying the chute L. The casting or ring M is supported directl uponthe flanged upper end of the chute E and in turn carries a section W ofthe furnace proper which carries the-holder X for the upper electrode.An upper section Y is added, carrying chutes or spouts Z through whichthe material is fed,

a stack a for the discharge of the gases generated, and a stoking doorI).

In commencing the operation of the furnace a block'of iron or othersuitable material of the shape of the pig F is bolted or otherwisefastened to the-conveyer with its upper end near the carbon A as closeto it as possible. The arc being established and the materiall) beingfed in, a pool f liquid carbid is formed. Then as the reduction roceedsthe operator turns the hand wheel to move the conveyor down togetherwith the pig. When the resistance becomes too high the hand wheel T isstopped or turned more slowly. When the resistance becomes too low thehand wheel is turned more rapidly. The product F passes downward andprojects out of the end of the chute L where it is broken off in piecesof suitable size, the material D surrounding the pig being carried backto the reservoir and used over again.

The manner of controlling the rapidity of the process by holding u thepig so as to retain the molten materia in a die permits of the mostellicient utilization of the energy sup lied by the current, both as torapidit oft e process and uniformity and high qua ity of the product;and above all is extremely cheap compared with prior processes by reasonof the avoidance of a practically useless crust around the pig ofproduct. 7 By reason of the currents traveling through only the uppermolten part of the pig in passing from one electrode to the other Iavoid the loss of energy occasioned in previous single-arc furnaces bythe necessity of passing the current through the complete length of pigand maintaining the same substantially liquid; thus securing an outputquite as great as in a double-arc furnace. At the same time I am enabledto operate with a sin le arc and thus secure a product of uniformly oodquality throughout the cross-section 0% the pig; a thing which isimpossible with a double are because of the localization of the highestheat at oints immediately below the two arcs.

' he forming of the die of separate carbons B permits of maintaining thedie of a uniform size as the carbons wear or are burned off at theirinner ends. The amount of shortening of the carbons is compensated forby forcing the carbons inward as they wear l so that they constantlytouch each other or approximately so to form the die. The upperelectrode A may also be made adjustable in any suitable manner. 7

It is not essential to the process that the pig as it emerges from thedie shall be surrounded by the material D or any other nonconductingmaterial. The withdrawal of the, pig may of course be accomplished byconstantly-driven or automatic mechanism instead of the hand mechanismshown, and

such constantl -driven mechanism may be' controlled by and orautomatically. The

the essential point he mass specific form of conveyor shown is notessential to success, a {cat variety of conveyers being adapted to t 0same purpose.

A furnace difi'ering in some respects from that shown in Fig. 1 thoughembodying the same general principles of operation, 18 shown inFigs. 3,4 and 5. The diein this caseis formed of carbon plates B, constitutingthe lower electrode, and lower lates 0 preferably of graphite, firebrick or ot or material (conductive or not) which will not be injured byexposure to the high heat. The die tapers and is supported in a holderpreferably in the form of a casting d supported 'in turn upon legs orother suitable supports V. The u r electrode A may be arr ed with itsower end within the die as in ig. 6, but is shown in this case as sl'htly above the die, though not so high as to cm the solid pig or anyportion of it above the die so as to prevent its being drawn downward.The zone of fusion, or at least the pool of fused material, fills thecross-section of the die so that as the li uid solidifies it may bedrawn downward. 11 order to hasten the solidification of the materialbefore it asses out of the die (which solidification is esirable thoughnot essential) the lower carbon holder d may be provided with a jacketor tubular space e running entirely around it, through which cold watermay be passed. Any other suitable means may be utilized for cooling thedie or for cooling the pig directly. The pig may be drawn out in airectly vertical line A suitable means for holding up the pig andlowering it at a desired rate is shown. comprising a table f upon whichthe pig rests and which ma be lowered manually or mechanically. hen ithas been lowered to expose a desired len th of the pig F the latter maybe broken of? as for example at the point 9, and the broken off artremoved. lnwardly rojecting blades F1 or equivalent devices iiold u theremaining portion of the pig until the ta lef can be shoved up againstits bottom.

The mode of operation of the structure shown in these figures issubstantial y the same as that of the furnace of Fig. 1.

Fig. 6 illustrates certain additional modifications which may be madewithout departing from the spirit of the invention. The lower electrodeB is a solid. carbon block in the form or a die with its aperture ofuniform cross section throughout its length. The upper electrode A maybe elevated above the die a slight distance as in Figs. 1 and 3, wasshown it may extend down within the die; to avoid placing it high enoughabove the ie to permit the partial solidification of the fused materialbefore it can enter the u per end of the die. The feature of BXtCDt ingthe upper electrode down within a lower electrode however is not claimedas my invention. In thisfigure means are indicated for re upper carbonA, either for adjusting it for wear or for permitting its gradualmovement from the lower part of the die to the u r part in the carryingout of the process. 's means ma consist of a contro wheel 7' the hub 0which is screw-threade and enages a screw-threaded end of a rod I:carrygulating the height of the mg the electrode. For lowering ordrawing down the pig F a pair of roughened rollers In? be provided,geared together as shown one of them carried on a shaft m conrolled byany suitable operatintg device or mechanism, such as the ban -controlledworm shaft m. The lower electrode in this case is supported in a shellof metal 1t constituting the principal portion of the wall of thefurnace proper, the upper carbon holder 1: being supported from the topof the furnace as indicated. In every case suitable insulation'o isprovided between the parts of the furnace carrying the upper and lowerelectrodes. The wall of the electrode or die B is tapered at its upperend to ide all the material toward the opening 0 the die.

Fig. 7 shows the application of the princile to a double-arc furnace,that is to say, a ace in which there is an are between each of twoelectrodes and the fused material. The electrodes A and B may be mountedsimilarly to the upper electrode of Fig. 6 or in any other suitab e way.The die p is composed of bricks of strong heat-resisting mate-' rial,preferably graphite, and may be supported in a shell 12. similar to thatof Fig. 6. l he passage through the die may be of uniform cross-sectionas shown, or may be tapered as in Figs. 1 to 5. By making the dielarger, or arranging the electrodes A and B closer together, they may belowered into the die. Or they may be arranged as shown a slight distanceabove the top of the die so that the solid product is formed directly inthe die. The withdrawal of the solid pig may be effected by oovedrollers."

In commencing t e operation of the furnace shown in Figs. 3 to 7, aniron box or other block of suitable material is arranged with its top sohigh as to support the molten material in proximity to the u perelectrode or electrodes, and is gradually owered as the pig is formed.It is understood that the arc is ormed in the first place'in each of theseveral furnaces by introducing some of the mixture on top of the falsebottom and adding broken coke or other form of carbon on to of thisuntil it touches the upper electrode, a ter which the current is turnedon and the material is fed in in suitable quantities. The rollers l ofFigs. 6 and 7 may be held against the ig with a yielding pressure, ormay be rigitPas shown. Preferably their turning is controlled by a wormwheel (see Fig. 6) so that they are automatically locked in any positionto which they are moved. Likewise o I a worm wheel or equivalent lockingmechanism should be used to control'the movement of the table 1' ofFigs. 3 and 4. The length of the dies will vary with the material to beformed. With a product which solidifies at a very high temperature asolid pig will be formed a short distance below the upper electrode, andfor this product a comparatively short die such as is shown in Fig. 1will be suflicient. For a product which solidifies at a lowertemperature or more slowly the die will be longer, and it may even benecessary to apply special cooling means such as described for-insuringthat it shall be sufliciently hard to be handled in a pig when itemerges from the die. I It may of course be slightly plastic so that asit emerges it s reads out laterally to a slight extent, and or the mostefficient carrying out of the process it should be sulliciently stiff tobe he d up and in turn to hold up the fused material above it. It shouldhave a solidified shell capable of retaining the hotter and still liquidmate? rial in the center at the time that it emerges from the die, andthe point at which the end of the pig is broken off should besulliciently far away from the die to permit of the solidification ofthe material throughout its crosssection.

The differences in detail presented b the several dii'l'erentforms ofthe invention s iown are in general interchangeable. That is to say, afurnace may be built comprising any desired features selected from eachof the several furnaces described.

In previous ingot furnaces the lime and carbon had to be very finelyground so that the molten lime should not percolate too freely into thematerial outside of the zone of fusion and thus form a pig of irregularquality and pith a thick crust. With my improved apparatus in which allthe material passes through the zone of fusion and is reduced therein,the former expense for fine grinding is not necessary. Also in previousingot furnaces it has been found im racticable to use limestone, thecrust forme case'being very hard as compared with that obtained by theuse of lime. With my improved apparatus producing a crustless pig,limestone may be substituted for lime with a considerable saving inexpense.

Though I have described with great particularity of detail certainembodiments of my invention, yet it is not to be understood that theinvention is limited to the particular embodiments described.' Variousmodifications thereof in detail and in the arrangement and combinationof the parts may be made; by those skilled in the art without departurefrom the invention.

What I claim is 1. In an electric furnace for the produc tion of calciumcarbid or the like, means for in such a "e'fdsely circumscribing suchzone, and means for progressively passing all the material to beutilized in forming the product within'said walls and through sa d zoneof fusion and dischargin it in solidified form, said means engagin thesolidified product, whereby is obtaine a pig devoid of crust.

2. In an electric furnace for the producmaintaining a zone of fusion inwhich the material is fused, adie having walls closely c'ircumscribingsuch zone, and means for withdrawing the material from said dieprogressivel as it solidifies and thus holding up the fuse materialwithin said die.

3. In an electric furnace for the producfor fusing the material, and adie thro h which the fused material passes and by which it is shaped,and which separates the unreduced material above from the reducedmaterial beneath, and means for withdrawing the material from said dieprogressively as it solidifies and thus holding up the fused materialwithin said die.

4. An electric furnace having a die through which the material passes,means for fusing the material within such die, said die adapted toretain the product until it is sufficiently solidified to emerge in asolid pig, and means for controlling the rate of emergence of said 5. Anelectric furnace havin a die through which the material passes, said dieformed of rcfracto I conductin material and serving as one (if theelectrodes, a' second electrode suitable current passes between them thematerial within the die is fused and reduced, and means for controllingthe passage of material through the dle adapted to retain the producttherein until it is sufiiciently solidified to emerge in a solid pig.

6. An electric furnace having a die composed of sections of carbonformin an electrode, said sections being adapted for radial adjustment.

7. An electric furnace having a die through Y which the material passes,means for fusing the material within the upper portion of such die, saiddie prolonged sufficiently below the zone of such fusion to permit thefused product to sufficiently solidify within the die to emergetherefrom in a solid pig, and the die flare at its discharge end tofacilitate the emergence of such pig.

- 8. An electric furnace having a die through which the material passes,means for fusin the material within the upper portion of sucl die, andmeans for cooling the lower portion of such die, whereby the moltenproduct is sufficiently solidified within the die to emerge therefrom ina solid. pig.

9. An electric furnace having a die, means for fusing all the materialwhich passes tion of calcium carbid or the like, means for.

tion of calcium carbid or the like, means arranged adjacent theretowhereby when a amass through said die, a chute on the discharge side ofthe die, and means for feeding between the chute and the solidifiedroduct emerging from said die a quantity 0 granular material.

10. An electric furnace having a die, means for passing a portion of thematerial throu h said die and fusing the same, and means or pasgin aportion of the material outside of sex emerging from the die.

e and about the solidified product 11. An electric furnace having afixed curved chute, and means for conveying the reduced material in acurved pig through said chute.

In witness whereof, I have hereunto si ed my name in the presence of twosubscri ing witnesses.

JESSE CRITZ KING.

Witnesses:

DOMINGO A. USINA, FRED Wm.

